More on enzymes

In the amylase/starch experiment, you need to choose which variable to change, e.g.

to investigate the effect of the temperature, put the test tubes into water baths at a range of temperatures.

to investigate the effect of pH, use a range of different pH buffers.

to investigate the effect of substrate concentration, vary the initial concentration of the starch solutions.

Measuring the rate of an enzyme-controlled reaction - results

Enzymes like it warm but not too hot-

Changing the temperature changes the rate of an enzyme-catalysed reaction. Like with any reaction, a higher temperature increases the rate at first. This is because more heat means the enzymes and the substrate particles have more energy. They move about more, so they're more likely to meet up and react.